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  • 1
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 3 (1970), S. 165-171 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The errors inherent in the usual method of correcting for the spectral distribution in the variance method of profile analysis, i.e. the subtraction of the variance-range function of the spectral distribution from that of the powder line profile, are studied in detail. It is shown, using a fairly general model, that additivity of variances holds very well for slopes but rather poorly for intercepts of linear variance-range functions. An approximate expression for the additivity error is given.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 4 (1971), S. 319-321 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: A previous paper by Edwards & Toman on the subject of the variance non-additivity and curvature corrections is revised and extended. The formula for the curvature correction is given in a form which facilitates evaluation for cases of crystallite size broadening by crystallites of known shape; the formula involves the shape parameter M which is evaluated for the shapes of a sphere, a rectangular parallelepiped, a tetrahedron and an octahedron.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 4 (1971), S. 472-478 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The X-ray diffraction lines from twelve powder samples of iron and high-speed steel with various mesh sizes and chemical compositions were measured and the data analysed using the centroid and variance as measures of line position and width. Values of lattice parameter, apparent crystallite size and mean lattice strain were found and interpreted in terms of the composition and previous history of each sample. In all cases the powder particles were found to be fragmented into many hundreds of crystallites and there was no correlation between particle size and crystallite size. The application of the non-additivity, curvature and satellite-group corrections previously introduced is described and attention drawn to the effect of the multiplicity factor in reducing the dependence of apparent size on hkl.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 4 (1971), S. 43-50 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The variance of the X-ray spectral distribution in the Cu Kα multiplet has been redetermined with improved accuracy and over a wider range than previously. This investigation is parallel to that of Edwards & Toman on iron radiation, with which comparison is made on the following points: (i) the effect of using a β-filter and (ii) the effect of interpolating the line profile under the Kα satellite group. Both definitions of the variance are considered and three linear regions can generally be distinguished in the variance–range function. The choice of definition and the usefulness of the different linear regions in any practical application are also discussed.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 3 (1970), S. 157-164 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Three methods are described of eliminating the influence of the satellite group in the variance method of X-ray line profile analysis. The first is to interpolate the line profile under the satellite group: however, the satellite group must be reasonably well distinguished from the α1 tail and from the background. The second method is to correct the experimental variance-range curve by a graphical construction: this assumes that the satellite lines and the broadening function are Cauchy in form. The third method is to compute the necessary corrections to the slope and intercept of the linear variance-range function by using model spectral distributions with and without the satellite group. The first two methods are applied to profiles from powders of iron and iron alloys studied with iron radiation, the third method uses an analytical model of the spectral distribution of the iron Kα multiplet. The corrections given by these methods to be made to the slope and the intercept of the variance-range function are nearly constant for all but the smallest amounts of particle-size broadening. It is also shown that particle sizes determined either from slope or intercept of the variance will be underestimated if correction is not made for the satellite group.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 4 (1971), S. 332-333 
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 236 (1972), S. 230-232 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 'Sephadex' gel filtration of samples 'from three birds dosed orally with 65Zn. Graph was obtained from one bird representative of the three, a, Blood plasma elution 'Sephadex G-150' column, b, Intestinal mucosa soluble fraction elution by 'Sephadex G-150' columns, c, Intestinal digesta ...
    Type of Medium: Electronic Resource
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